This invention generally relates to filters for maintaining aquariums. More particularly, but not by way of limitation, the invention is directed at a new, novel apparatus for filtering conventional aquariums which utilize a single-piece, absorbent sponge and requires no enclosure, no charcoal filter, nor any filter floss.
Presently available filters for aquariums come in two general types. The first requires an enclosure into which is packed various filtering agents such as charcoal or synthetic floss. The second general type of filter is a bottom plate (commonly referred to as an underground filter) which is placed on the bottom of an aquarium and covered with gravel so that the entire floor of the aquarium acts as a filter. Both general types of aquarium filters are difficult and cumbersome to maintain because of the difficulty in the required periodic cleaning. The first type requires removal from the aquarium, stripping of its various internal components, cleaning of these components, and then replacement of the filtering agents before reusing in the aquarium. The second type is even more difficult to clean as it requires an extensive rearrangement of the entire aquarium; the entire floor and gravel on top of it must be cleaned and then redistributed. Thus, there is a need for an aquarium filter which is of simple construction, easy to install and requires minimum maintenance.
To overcome the above problems, a third type of filter similar to the present invention has been produced (See Prior Art FIG. 5). That conventional filter consists of a core assembly including a stem socket over which is fitted a bubble tube. The core further has an opening in its center and is surrounded by a sponge. A small orifice has been placed toward the bottom of the bubble tube so that an air tube may be fitted into that tube. As air bubbles are introduced into the water contained in the bubble tube, a difference in pressure between that water and the water surrounding the sponge in created. That difference in pressure forces water through the sponge and up the bubble tube thereby trapping dirt and other particles in the sponge and returning clean water back to the aquarium.
There are two problems with the above conventional configuration. First, as shown in FIG. 5, the air tube is merely inserted into the hole at the bottom of the bubble tube and is held only by the pressure between that tube and the bubble tube. During continuous operation, the air tube in many instances will be dislodged from the bubble tube by the vibrations caused in introducing air bubbles into the bubble tube. If that occurs, all filtering of the aquarium water will cease, and if that situation goes unnoticed for any length of time, harm to the plant and animal life in the aquarium could result. Second, the uncontoured flat outer surface of the sponge provides a small surface area for the removal of dirt and other particles. This greatly diminishes the cleaning capacity of that type conventional sponge filter. Thus, the present invention provides for an aquarium filter arrangement that maximizes filtering capacity while minimizing filter malfunctions.